Air pressure compensation arrangement for a cartridge and writing or drawing instrument

ABSTRACT

An arrangement for sealingly connecting a cartridge containing writing fluid to a writing or drawing instrument includes passageway means which are arranged to permit air to escape between the cartridge and the writing or drawing instrument as the cartridge is being inserted in place, thereby avoiding undesirable entrapment of air between the cartridge neck and the writing instrument which would otherwise tend to effect a pressure buildup and result in leakage of the writing fluid.

United States Patent Gottschalk [75] Inventor: Claus Gottschalk, Nurnberg,

Germany [73] Assignee: Firma J .S. Staedtler, Nurnberg,

'Germany [22] Filed: July 18, 1974 [21] Appl. No.: 489,627

[30] Foreign Application Priority Data Aug. 3, 1973 Germany 7328357[U] [52] US. Cl. 401/135 [51] Int. Cl. 843K 5/14 [58] Field of Search 401/132-135 [56] References Cited UNITED STATES PATENTS 3,606,556 9/1971 Green et al. 401/133 X 3,910,707 Oct. 7, 1975 FOREIGN PATENTS OR APPLICATIONS 487,742 5/1970 Switzerland 401/133 Primary Examiner-Lawrence Charles Attorney, Agent, or Firm-Frank J. Jordan ABSTRACT 10 Claims, 8 Drawing Figures US. Patsnt Oct. 7,1975 Sheet 1 of2 3,910,707

Sheet 2 of 2 3,91

U.S. Patent Oct. 7,1975

AIR PRESSURE COIVIPENSATION ARRANGEMENT FOR A CARTRIDGE AND WRITING OR DRAWING INSTRUNEENT BACKGROUND OF THE INVENTION This invention relates generally to writing, drawing or drafting devices and more particularly to such devices which provide for air pressure compensation. Devices of this type provide for connecting a cartridge of India ink or the like to drawing pens, fountain pens and the like instruments having a writing head or other writing means. The devices are furnished with a cartridge neck which may be clampingly and sealingly inserted into an annular slot in the writing instrument.

At the present time writing, drawing, and drafting devices or instruments which use liquid inks or liquid dyes are usually provided with cartridges for the liquid ink or liquid dye supply. In such cases the writing head and cartridge are sealingly connected. Experience indicates that air which was contained in the connecting end of the writing head and in the neck of the cartridge tends to force the remaining ink or liquid outwardly during the process of connecting the cartridge to the writing head.

Heretofore, a cartridge neck construction is known where a groove or a recess is utilized. However, such groove or recess is not provided for air pressure compensation but rather as a guiding surface for a piercing means integrally connected to the writing head.

Another known construction of a cartridge neck provides approximately radially directed groove-shaped recesses within a stop face but this radial groove construction makes it possible for only extremely small volumes of gas to emerge because the grooves are closed off after a very short path of the writing head cylinder. This known construction also requires very complicated tools for manufacturing the cartridge for the liquid.

The previously known constructions are not satisfactory because there is still always a relatively large volume of gas present such that the internal pressure tends to build up as the cartridge neck is inserted on the writing head.

Accordingly, an object of the present invention is to overcome the disadvantages of these known prior art arrangements and to provide a cartridge connection which on the one hand effects a good seal between the cartridge and the writing head, and which is also capable of equilibrating the exchange of air up to shortly before the cartridge reaches its final seated position on the writing hand.

According to the present invention the aforementioned object is achieved by providing grooves or chamfers beginning at the free end of the cartridge neck and/or the connecting end of the writing head and extending along the inner and outer clamping surfaces. The axial length of the grooves or chamfers is less than the axial extension of the clamping surface so that the air sealing action occurs only shortly before the final end stop where the cartridge reaches its final seated position.

This construction of the cartridge neck and/or the connecting end of the writing head insures that the enclosed air may escape through the grooves and/or chamfers during the inserting operation without an increase of pressure in the system, which would tend to lead to cause spilling of ink or liquid out of the writing tip or out of the equilibrating system. The sealing action occurs only at the relatively low level end of its use, and spilling of ink or liquid is prevented because the pressure buildup is almost negligible.

A particularly simple embodiment of the invention consists, as mentioned above, of providing a cartridge neck having at least one chamfer on its outer clamping surface and a writing head having at least one chamfer on its inner clamping surface. A reverse possibility would be to provide the cartridge neck with at least one groove as described above at its inner clamping surface and to provide the writing head at its outer clamping surface with at least one groove as described above.

In order to reduce changes of the tools for the manufacture of one part only, either the writing head or the cartridge, a further embodiment of the present invention provides that the writing head is provided on its inner clamping surface with at least one chamfer and on its outer clamping surface with at least one groove as described above. Another embodiment may provide that the cartridge neck has at least one chamfer, and on its inner clamping surface at least one groove of the kind described above.

Other features which are considered characteristic of the invention are as set forth in the appended claims.

Although the invention is illustrated and described in relationship to specific embodiments, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.

The construction and operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

SUMMARY OF THE INVENTION An arrangement is provided for connecting a cartridge containing writing liquid with a writing head wherein the cartridge has a'neck insertable within an annular slot in the writing head. The annular slot and the cartridge neck have inner and outer annular surfaces. At least a portion of the inner annular surface of the writing head is adapted to sealingly mate with a corresponding portion of the inner annular surface of the cartridge neck. Also at least a portion of the outer annular surface of the writing head is adapted to sealingly mate with a corresponding portion of the outer annular surface of the cartridge neck. Longitudinally extending passageway means are provided in at least two of the annular surfaces providing for egress of air from the annular slot as the cartridge neck is being inserted in the annular slot in the writing head. The passageway means have axial lengths shorter than the respective axial lengths of the inner and outer annular surfaces so that sealing is not effected between the mating annular surfaces until just before the cartridge neck reaches its seated position in the writing head.

BRIEF DESCRIPTIONS OF THE DRAWINGS FIG. 1 is a partial longitudinal sectional view of a writing head and cartridge according to one embodiment of the invention.

FIG. 2 is a sectional view taken along the line [1-11 of FIG. 1.

FIG. 3 is a partial longitudinal sectional view of a writing head and cartridge according to another embodiment of the invention.

FIG. 4 is a sectional view taken along the line IVIV in FIG. 3.

FIG. is a partial longitudinal sectional view of a writing head and cartridge according to yet another embodiment of the invention.

FIG. 6 is a sectional view taken along the line VIVI in FIG. 5.

FIG. 7 is a partial longitudinal sectional view of a writing head and cartridge according to a further embodiment of the invention.

FIG. 8 is a sectional view taken along the line VIII- VIII in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, there is shown a writing head 1 of an India ink pen or similar type instrument which has on its connecting end an annular slot 2 within which a cartridge neck 3 of an ink or India ink cartridge 4 is adapted to be received in a mating rela tionship. The writing head 1 is provided with channels 5 through which the writing or drafting fluid is capable of passing to the tip of the pen or the writing tubule, the pen or tubule not being shown in the drawings. As indicated in the drawings, the writing head 1 may be provided with a thread 6 in order to threadedly receive a non-illustrated mounting part.

The cartridge 4 is provided with a shoulder 7 in order to determine the end stop position of the cartridge 4 relative to the writing head 1 as the shoulder 7 abuts against and rests against a free rim 8 on the writing head 1. The annular slot 2 at the connecting end of the writing head I is defined by an outer clamping surface 9 and an inner clamping surface 10. The cartridge neck 3 has an outer clamping surface 1 l and an inner clamping surface 12 which mate and rest upon the clamping surfaces 9 and 10 respectively of the writing head 1.

In order to provide for air equilibration while slidingly introducing the cartridge 4 onto the writing head 1, grooves or chamfers are provided in the respective clamping surfaces. The axial length of these grooves or chamfers is slightly shorter than the axial extension or axial length of the respective clamping surfaces so that a complete sealing length or sealing contact of the clamping surfaces of 0.2 to 1 mm results. The air residing inside between the writing head 1 and the cartridge neck 3 can escape over the free end 13 or 13 of the cartridge neck 3 when the cartridge 4 is in the broken line position in FIG. 1. It can be seen that the aforementioned sealing is effected shortly after the cartridge 4 is moved from the broken line position indicated at 13' to the seated position indicated at 13.

FIGS. 1, 3, 5 and 7 show various possible arrangements of grooves and chamfers which function as described above. FIGS. 2, 4, 6 and 8 show the respective cross-section as will be apparent in the drawings.

In the embodiment of FIGS. 1 and 2 the inner clamping surface 10 of the writing head 1 has a chamfer l4 and the outer clamping surface 11 of the cartridge neck 3 has a chamfer 15.

FIG. 3 shows an alternate embodiment of the present invention without any change of the cartridge neck 3. In this embodiment the inner clamping surface 10 of the writing head 1 is provided with a chamfer l4, and

the outer clamping surface 9 of the writing head 1 is provided with a groove 16.

FIG. 5 shows another alternate embodiment in which only the cartridge neck 3 is provided with a groove and a chamfer. In this embodiment the inner clamping surface 12 of the cartridge neck 3 is provided with a groove 17, and the outer clamping surface 11 of the cartridge 11 of the cartridge neck 3 is provided with a chamfer 15.

FIG. 7 shows a further alternate embodiment in which the outer surface 9 of the writing head 1 and the inner clamping surface 12 of the cartridge neck 3 are provided with the grooves 16 and 17 respectively.

It is thought that the invention and many of its attandant advantages will be understood from the foregoing description and that it will be apparent that various changes may be made in the form, construction, and arrangements of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages. The form heretofore described being merely a preferred embodiment thereof.

What is claimed is:

1. An arrangement for connecting a cartridge containing a writing liquid with a writing head wherein the cartride has a neck insertable within an annular slot in the writing head, the combination wherein said annular slot and said cartridge neck have inner and outer annular surfaces, at least a portion of said inner annular surface of said writing head being adapted to sealingly mate with a corresponding portion of the inner annular surface of said cartridge neck, at least a portion of said outer annular surface of said writing head being adapted to sealingly mate with a corresponding portion of the outer annular surface of said cartridge neck, said sealing mating being effected as said cartridge neck is being inserted within said annular slot in said writing head, longitudinally extending passageway means in at least two of said annular surfaces providing for egress of air from said annular slot as the cartridge neck is being inserted in said annular slot in said writing head, said passageway means having axial lengths shorter than the respective axial lengths of the inner and outer annular surfaces so that complete circumferential sealing is effected between said mating annular surfaces just before the cartridge neck reaches its seated position on the writing head.

2. An arrangement according to claim 1 wherein said cartridge neck has a terminating end, at least one of said passageway means being formed in said cartridge neck and extending from said terminating end.

3. An arrangement according to claim 1 wherein said writing head has a terminating end defining the longitudinal end of said annular slot, at least one of said passageway means being formed in the annular surface defining said annular slot and extending from said terminating end.

4. An arrangement according to claim 1 wherein said passageway means is formed by at least one chamfer on the outer annular surface of said cartridge neck and at least one chamfer on the inner'annular surface of said annular slot.

5. An arrangement according to claim 1 wherein said passageway means is formed by at least one groove on the inner annular surface of said cartridge neck and at least one groove in the outer annular surface of said annular slot.

8. An arrangement according to claim 1 wherein the longitudinal length of said mating and sealing surfaces is about from 0.2 to 1 mm.

9. An arrangement according to claim 1 wherein said passageway means is formed by a chamfer on at least one of said annular surfaces.

10. An arrangement according to claim 1 wherein said passageway means is formed by a groove in at least one of said annular surfaces. 

1. An arrangement for connecting a cartridge containing a writing liquid with a writing head wherein the cartride has a neck insertablE within an annular slot in the writing head, the combination wherein said annular slot and said cartridge neck have inner and outer annular surfaces, at least a portion of said inner annular surface of said writing head being adapted to sealingly mate with a corresponding portion of the inner annular surface of said cartridge neck, at least a portion of said outer annular surface of said writing head being adapted to sealingly mate with a corresponding portion of the outer annular surface of said cartridge neck, said sealing mating being effected as said cartridge neck is being inserted within said annular slot in said writing head, longitudinally extending passageway means in at least two of said annular surfaces providing for egress of air from said annular slot as the cartridge neck is being inserted in said annular slot in said writing head, said passageway means having axial lengths shorter than the respective axial lengths of the inner and outer annular surfaces so that complete circumferential sealing is effected between said mating annular surfaces just before the cartridge neck reaches its seated position on the writing head.
 2. An arrangement according to claim 1 wherein said cartridge neck has a terminating end, at least one of said passageway means being formed in said cartridge neck and extending from said terminating end.
 3. An arrangement according to claim 1 wherein said writing head has a terminating end defining the longitudinal end of said annular slot, at least one of said passageway means being formed in the annular surface defining said annular slot and extending from said terminating end.
 4. An arrangement according to claim 1 wherein said passageway means is formed by at least one chamfer on the outer annular surface of said cartridge neck and at least one chamfer on the inner annular surface of said annular slot.
 5. An arrangement according to claim 1 wherein said passageway means is formed by at least one groove on the inner annular surface of said cartridge neck and at least one groove in the outer annular surface of said annular slot.
 6. An arrangement according to claim 1 wherein said passageway means is formed by at least one chamfer on the inner annular surface of said annular slot and at least one groove formed in the outer annular surface of said annular slot.
 7. An arrangement according to claim 1 wherein said passageway means is formed by at least one chamfer formed on the outer annular surface of said cartridge neck and at least one groove in the inner annular surface of said cartridge neck.
 8. An arrangement according to claim 1 wherein the longitudinal length of said mating and sealing surfaces is about from 0.2 to 1 mm.
 9. An arrangement according to claim 1 wherein said passageway means is formed by a chamfer on at least one of said annular surfaces.
 10. An arrangement according to claim 1 wherein said passageway means is formed by a groove in at least one of said annular surfaces. 